The present invention relates to a semiconductor device and a semiconductor device manufacturing method.
As wiring is increasingly miniaturized, it is demanded that an effective dielectric constant be decreased. Particularly, the dielectric constant of a barrier insulating film for preventing the diffusion of wiring metal is relatively high. It is therefore demanded that the dielectric constant of the barrier insulating film be decreased. Studies have been conducted to decrease the dielectric constant of the barrier insulating film, for instance, by using a barrier insulating film made of a substance having a high organic component content such as C-rich SIGN, C-rich SIC, or C-rich SiCO. Meanwhile, the barrier insulating film can be thinned as described in Japanese Patent Application Publication No. 2009-182000.
The technology described in Japanese Patent Application Publication No. 2009-182000 prepares a barrier insulating film having a laminated structure in such a manner that it partially includes a high-density film, which has a high film density. It is also disclosed that the barrier insulating film having a laminated structure partially includes a silicon nitride film. Japanese Patent Application Publication No. 2009-182000 states that the use of the above barrier insulating film, which is thinned and configured to prevent the permeation of extraneous water, decreases the effective dielectric constant.
According to Japanese Patent Application Publication No. 2009-182000, the barrier insulating film includes the silicon nitride film, which provides high resistance to water permeability. This makes it possible to prevent the permeation of water without increasing the thickness of the barrier insulating film. Hence, Japanese Patent Application Publication No. 2009-182000 states that the effective dielectric constant can be decreased while preventing the permeation of extraneous water. However, the inventors of the present invention have found that considerable current leakage occurs in the silicon nitride film included in the barrier insulating film. Consequently, a semiconductor device with a highly reliable barrier insulating film having a low effective dielectric constant is demanded.
According to one aspect of the present invention, there is provided a semiconductor device including an interlayer insulating film, wiring laid in the interlayer insulating film, and a Si-and-N contained insulating film formed over the interlayer insulating film and over the wiring. The peak positions of Si—N bonds of the SiN film, which are measured by FTIR (Fourier transform infrared spectroscopy), are within the range of 845 cm−1 to 860 cm−1.
The inventors of the present invention have found that there is current leakage in the silicon nitride film included in the barrier insulating film due to Si—H bonds and dangling bonds possessed by the silicon nitride film. According to an embodiment of the present invention, the peak positions of Si—H bonds of the SiN film, which are measured by FTIR, are within the range of 845 cm−1 to 860 cm−1. It indicates that the Si—H bonds and dangling bonds are decreased in number. As described above, the SiN film according to an embodiment of the present invention is such that the Si—H bonds and dangling bonds are decreased in number. Therefore, the current leakage in the silicon nitride film can be inhibited. This makes it possible to provide a semiconductor device with a highly reliable barrier insulating film having a low effective dielectric constant.
According to another aspect of the present invention, there is provided a semiconductor device including a first interlayer insulating film, wiring laid in the first interlayer insulating film, and a Si-and-N-contained insulating film formed over the first interlayer insulating film and over the wiring. The composition ratio of N/Si in the Si-and-N-contained insulating film, which is measured by XPS (X-ray photoemission spectroscopy), is within the range of 0.9 to 4/3.
According to still another aspect of the present invention, there is provided a semiconductor device including a first interlayer insulating film, wiring laid in the first interlayer insulating film, and a Si-and-N-contained insulating film formed over the first interlayer insulating film and over the wiring. The spin density due to dangling bonds in the Si-and-N-contained insulating film is not higher than 1E17 spins/cm3.
According to yet another aspect of the present invention, there is provided a semiconductor device manufacturing method including the steps of: laying wiring in an interlayer insulating film, forming a N-contained insulating film over the interlayer insulating film and over the wiring, and performing an enhanced nitridation process on the N-contained insulating film.
The present invention makes it possible to provide a semiconductor device with a highly reliable barrier insulating film having a low effective dielectric constant.